1. Field of the Invention
The present invention relates to a printer system and more particularly to a printer system for controlling the power supply of a network printer.
2. Discussion of the Background
A printer system for controlling the power supply of a network printer has been proposed in various forms in the past. Japanese Patent Laid-Open Publication No. 5-345460, for example, discloses a printer system in which a printer turns on or turns off its large capacity power supply section in response to data received from, e.g., a host computer. This printer system is directed toward power saving. Japanese Patent Laid-Open Publication No. 8-238822 teaches a printer system in which a printer turns on its power supply only during printing data so as to reduce power consumption. Further, Japanese Patent Laid-Open Publication No. 9-258857 proposes a printer system in which a printer turns on or turns off power supply to its printing parts in response to a command received from a host.
Generally, in a printer system, a number of users share a single network printer. Therefore, a problem with the above conventional printer system is that although the printing speed available with the printer may be high, one user cannot easily occupy the printer or perform another work when another user is producing a great amount of printings with the printer. Should the power supply of the printer be constantly turned on to allow all the users belonging to the system to use the printer anytime, the printer would wastefully consume power.
In light of the above, the power supply of the network printer may be turned on only when printing data and turned off thereafter by remote control, as in any one of the conventional printer systems. This successfully minimizes the power consumption of the network printer, but gives rise to the following problems. Assume that one user turns off the power supply of the printer by remote control, determining that the other user terminals are not operating, despite that any one of the other users is operating the user terminal or intending to access the printer. Then, the other users cannot access the printer at all. Further, when any one of the users issues a print job while the power supply of the printer is turned off, the user cannot use the printer indefinitely.
It is therefore an object of the present invention to provide a printer system allowing a network printer to turn on or turn off its power supply on the basis of remote control and thereby promoting easy and efficient use of the printer.
A printer system of the present invention includes a plurality of client computers and a single network printer selectively connectable to the client computers via a server computer. A power supply control section is included in the printer for selectively turning on or turning off the power supply of the printer in response to remote control effected from any one of client computers via the server computer. A confirming section is also included in the printer for confirming, in response to a power OFF command received from any one of the client computers, the connection of client computers other than one sent the power OFF command. The power supply control section turns off the power supply if allowed on the basis of information output from the confirming section and representative of the connection of the other client computers.